Tribenzylammonium octamolybdate and composition containing same

ABSTRACT

Tribenzylammonium octamolybdate is disclosed as a novel amine molybdate and as a smoke retardant additive for vinyl chloride and vinylidene chloride polymer compositions.

BACKGROUND OF THE INVENTION

Amine molybdates may be produced by reacting an amine with a molybdenumcompound such as molybdenum trioxide (MoO₃), molybdic acid or amolybdenum salt in an acidic aqueous medium made acidic through theaddition of a suitable acid such as an organic acid containing 1 to 12carbon atoms (exemplified by acetic acid, propionic acid, benzoic acid,and the like) or an inorganic acid (exemplified by hydrochloric acid,nitric acid or sulfuric acid). The acidic mixture is refluxed,preferably while being stirred continuously, until the reaction iscomplete, usually for about 1/4 to 4 hours.

Amine molybdates also may be produced, as described in my co-pendingapplication Ser. No. 016,583, filed Mar. 1, 1979 and entitled "ProcessFor Making Amine Molybdates", by reacting essentially stoichiometricquantities of molybdenum trioxide with an amine in an aqueous mediumessentially free of acid and in which a water-soluble ammonium ormonovalent metal or divalent metal or trivalent rare earth metal salt ofan inorganic or organic acid is dissolved.

The particular amine molybdate formed may depend upon which process isused to form the amine molybdate and the quantity of reactants presentin the reaction mixture, as well as the reaction conditions.

SUMMARY OF THE INVENTION

The present invention pertains to a novel amine molybdate, namely,tribenzylammonium octamolybdate, which has the empirical formula [H(C₆H₅ CH₂)₃ N]₆ (Mo₈ O₂₇).4H₂ O and which exhibits major x-ray diffractionpeaks at "d" spacings of 13.0 A, 9.09 A, 4.80 A and 4.27 A. It isbelieved that the amine molybdate normally exists as a polymericstructure and, thus, may be represented by the formula

    [H(C.sub.6 H.sub.5 CH.sub.2).sub.3 N].sub.6n (Mo.sub.8 O.sub.27).sub.n.4.sub.n H.sub.2 O,

where n is an integer of 1 or more. Like many other amine molybdates,tribenzylammonium octamolybdate functions as an effective smokeretardant additive for vinyl chloride and vinylidene chloride polymers.

DETAILED DESCRIPTION OF THE INVENTION

Tribenzylammonium octamolybdate may be produced by reacting ammoniumdimolybdate [(NH₄)₂ Mo₂ O₇ ] and tribenzyl amine in essentially a 2/1molybdenum/tribenzylamine molar ratio in an acidic aqueous medium.Suitable acids include inorganic acids such as hydrochloric acid, nitricacid, sulfuric acid, and the like, or mixtures thereof. The amount ofacid used may be varied widely from about 1/2 to 10 or more molarequivalents of acid per molar equivalent of ammonium dimolybdate.However, about a 1/1 molar equivalent ratio is preferred. Sufficientwater is included in the reaction mixture to insure a reaction mediumthat has a consistency that enables it to be easily stirred. Desirably,the ammonium dimolybdate is dissolved in water and is added to an acidicsolution of the tribenzylamine. If preferred, the ammonium dimolybdate,tribenzylamine acid and water can be charged essentially simultaneouslyto the reaction vessel. The reaction materials desirably are refluxedwhile being stirred continuously for 0.25 to 16 hours. Although thereaction can occur at room temperature (25° C.), desirably the reactionmixture is heated to between 75° to 110° C. in order to reduce the timefor the reaction to be completed. After the reaction is completed, thecrystalline tribenzylammonium octamolybdate formed can be separated fromthe liquid phase by filtration, centrifugation or other suitableseparation means, washed with water, alcohol or a mixture of water andalcohol, and then dried. The reacted mixture may be cooled to roomtemperature (about 25° C.) before the separation of the solidtribenzylammonium octamolybdate from the liquid phase, although coolingthe mixture before separation of the solid product from the liquid phaseis not necessary. The recovered tribenzylammonium octamolybdate may beair dried, preferably at about 100° to 200° C., or may be vacuum dried,preferably at temperatures up to 150° C. and higher. Thetribenzylammonium octamolybdate is readily identifiable by elemental,infrared or x-ray diffraction analysis.

The following example illustrates the preparation of tribenzylammoniumoctamolybdate more fully;

EXAMPLE 1

10.00 grams of tribenzylamine, 6.86 grams of a 37 percent hydrochloricacid solution and 200 milliliters of water were added to a 500milliliter round-bottom flask equipped with a water-cooled condenser andwas brought to reflux. 11.83 grams of ammonium dimolybdate were added to50 milliliters of water and the mixture was heated until the ammoniumdimolybdate dissolved. The hot ammonium dimolybdate solution was addedto the flask and refluxed while being stirred continuously for 1/2 hour.The contents of the flask were cooled to room temperature (about 25° C.)and were filtered. A yellow crystalline solid was recovered. Therecovered solid was washed with water and vacuum dried for 100° C. forapproximately 16 hours. 16.69 grams of the crystalline solid wererecovered. Elemental, infrared and x-ray analysis identified the solidto be tribenzylammonium octamolybdate.

Tribenzylammonium octamolybdate has been found to be a smoke retardantadditive for vinyl chloride and vinylidene chloride polymercompositions. When used as a smoke retardant additive, tribenzylammoniumoctamolybdate desirably has an average particle size from about 0.01 toabout 800 microns, preferably from about 0.1 to about 100 microns, andis present in an amount from about 0.1 to about 20 parts by weight per100 parts by weight of the vinyl chloride or vinylidene chloridepolymer.

Vinyl chloride and vinylidene chloride polymers with which thetribenzylammonium octamolybdate can be used as a smoke retardantadditive include homopolymers, copolymers and blends of homopolymersand/or copolymers. The vinyl chloride and vinylidene chloride polymersmay contain from 0 to 50 percent by weight of at least one otherolefinically unsaturated monomer. Suitable monomers include 1-olefinscontaining from 2 to 12 carbon atoms such as ethylene, propylene,1-butene isobutylene, 1-hexene, 4-methyl-1-pentene, and the like; dienescontaining from 4 to 10 carbon atoms, including conjugated dienes suchas butadiene, isoprene, piperylene, and the like; ethylidene norborneneand dicyclopentadiene; vinyl esters and allyl esters such as vinylacetate, vinyl chloroacetate, vinyl propionate, vinyl laurate, alkylacetate, and the like; vinyl aromatics such as styrene, α-methylstyrene, chlorostyrene, vinyl toluene, vinyl naphthalene, and the like;vinyl allyl ethers and ketones such as vinyl methyl ether, allyl methylether, vinyl isobutyl ether, vinyl n-butyl ether, vinyl chloroethylether, methylvinyl ketone, and the like; vinyl nitriles such asacrylonitrile, methacrylonitrile, and the like; cyanoalkyl acrylatessuch as α-cyanomethyl acrylate, the α-, β- and γ-cyanopropyl acrylate,and the like, olefinically unsaturated olefinically unsaturated acidsand esters thereof including α,β-olefinically unsaturated acids andesters thereof such as methyl acrylate, ethyl acrylate, chloropropylacrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, dodecylacrylate, octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate,glycidyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate,hexylthioethyl acrylate, methyl methacrylate, ethyl methacrylate, butylmethacrylate, glycidyl methacrylate, and the like; and including estersof maleic and fumaric acid, and the like; amides of the α,β-olefinicallyunsaturated carboxylic acids such as acrylamide, and the like, divinyls,diacrylates and other polyfunctional monomers such as divinyl benzene,divinyl ether, diethylene glycol diacrylate, ethylene glycoldimethacrylate, methylene-bis-acrylamide, allyl pentaerythritol, and thelike; and bis (β-chloroethyl) vinyl phosphonate, and the like.

The vinyl chloride and vinylidene chloride polymer, in addition to thetribenzylammonium octamolybdate additive, may contain the usualcompounding ingredients known to the art such as fillers, stabilizers,opacifiers, lubricants, processing aids, impact modifiers, plasticizers,antioxidants, and the like.

Smoke retardancy may be measured using an NBS Smoke Chamber according toprocedures described in ASTM E662-79 "Test For Specific Optical DensityOf Smoke Generated By Solid Materials". Maximum smoke density (D_(m)) isa dimensionless number and has the advantage of representing a smokedensity independent of chamber volume, specimen size or photometer pathlength, provided a consistent dimensional system is used. Percent smokereduction is calculated using the equation: ##EQU1## The term "Dm/g"means maximum smoke density per gram of sample. Dm and other aspects ofthe physical optics of light transmission through smoke are discussedfully in the ASTM publication.

The smoke retardant property of tribenzylammonium octamolybdate isillustrated by the following examples.

EXAMPLES 2-4

The following recipe was used:

    ______________________________________                                        Material               Parts by Weight                                        ______________________________________                                        Polyvinyl Chloride Resin*                                                                            100.00                                                 Lubricant**            2.0                                                    Tin Stabilizer***      2.0                                                    Tribenzylammonium octamolybdate                                                                      varied                                                 ______________________________________                                         *Homopolymer of vinyl chloride having an inherent viscosity of about          0.98-1.04; ASTM classification GP5-15443.                                     **A commercial polyethylene powder lubricant (Microthene 510).                ***Tin Thioglycolate.                                                    

The ingredients of the recipe were dry-mixed and bonded on a two-rollmill for about 5 minutes at a roll temperature of about 165° C. Themilled compositions were pressed into 6×6×0.025 inch sheets. Pressingwas done at about 160° C. for 5 minutes using 40,000 pounds (about14,900 Kg) of force applied to a 4-inch ram. The sample received a 2minute preheat before being pressed.

The molded samples were cut into 27/8×27/8×0.50 inch sections. Testingwas performed using the flaming mode of the NBS Smoke Chamber Test (ASTME662-79) described heretofore. Test results are given in Table I.

                  TABLE I                                                         ______________________________________                                                  Tribenzylammonium       Smoke                                                 Octamolybdate           Reduction                                   Example   Parts by Weight                                                                              Dm/g*    %                                           ______________________________________                                        2 (control)                                                                             0              68.40    --                                          4         2.0            51.73    24                                          5         5.0            38.62    44                                          ______________________________________                                         *Dm/g = maximum smoke density per gram of sample.                        

The improved retardant vinyl chloride and vinylidene chloride polymercompositions obtained by the addition of tribenzylammonium octamolybdateto the compositions are useful wherever smoke resistance is desirable,such as in carpets, house siding, plastic components for airplane andpassenger car interiors, and the like.

I claim:
 1. Tribenzylammonium octamolybdate having the empirical formula[H(C₆ H₅ CH₂)₃ N]₆ (Mo₈ O₂₇).4H₂ O and having major x-ray diffractionpeaks at "d" spacings of 13.0 A, 9.09 A, 4.80 A and 4.27 A.
 2. A smokeretarded composition comprising a vinyl chloride or vinylidene chloridepolymer together with a smoke retardant amount of tribenzylammoniumoctamolybdate having the empirical formula

    [H(C.sub.6 H.sub.5 CH.sub.2).sub.3 N].sub.6 (Mo.sub.8 O.sub.27).4H.sub.2 O

and having major x-ray diffraction peaks at "d" spacings of 13.0 A, 9.09A, 4.80 A and 4.27 A.
 3. The smoke retarded composition of claim 2wherein said amine molybdate has an average particle size from about 0.1to about 100 microns.
 4. The composition of claim 2 wherein said aminemolybdate is present in an amount from 0.01 to about 20 parts by weightper 100 parts by weight of said polymer.